XML 141 R67.htm IDEA: XBRL DOCUMENT v3.19.1
PLANT AND EQUIPMENT AND MINERAL PROPERTIES - Schedule of Property, Plant and Equipment (Details) - USD ($)
$ in Thousands
Dec. 31, 2018
Dec. 31, 2017
Property, Plant and Equipment [Line Items]    
Cost $ 56,310 $ 56,203
Accumulated Depreciation (26,467) (23,127)
Net Book Value 29,843 33,076
Nichols Ranch    
Property, Plant and Equipment [Line Items]    
Cost 29,210 29,210
Accumulated Depreciation (12,021) (9,971)
Net Book Value 17,189 19,239
Alta Mesa    
Property, Plant and Equipment [Line Items]    
Cost 13,656 13,626
Accumulated Depreciation (2,319) (1,388)
Net Book Value 11,337 12,238
Equipment and other    
Property, Plant and Equipment [Line Items]    
Cost 13,444 13,367
Accumulated Depreciation (12,127) (11,768)
Net Book Value $ 1,317 $ 1,599